I think I could help these people. I could certainly see them as patients and learn to care. But I wouldn't particularly want to have them round for dinner.

Betrayal is a three-person drama that's all about the exclusion of one. You see a love triangle like this and you immediately think Oedipus.

Robert and Jerry, Emma's husband and her lover, are close friends but constantly compete. When Jerry talks to Emma about watching her marry Robert, he confesses his desire to "have her". That feeling hasn't got much to do with Emma. It's all about Jerry's competitive instincts.

I imagine this is a re-enactment of a childhood experience: losing a mother and competing with a father. The men talk about how boys can't bear to leave the womb. It's the idea that the close bond between a boy and his mother is threatened by the notion of the parents having a sexual relationship. This is an unmanaged early Oedipal situation disastrously re-enacted in adulthood.

The story of Jerry and Emma's affair is told backwards - but there was nothing unusual in that for me. As a therapist you're constantly picking up information from a complicated timeline.

The characters are post-pill and pre-feminism, casual about infidelity and dismissive of staying faithful. Their ability to turn a blind eye to their feelings would ring alarm bells with me if I were counselling them. All three are what I would call schizoid, in that they prohibit expressions of feeling. Only once does a character express any kind of emotional release or breakdown, and it's very difficult to see any guilt. They're appallingly narcissistic in their lack of remorse.

· Susanna Abse is a psychotherapist and director of the Tavistock Centre for Couple Relationships, London

· Betrayal is at the Donmar Warehouse, London (0870 660 6624), until July 21